The invention relates to refrigeration. More particularly, the invention relates to economizer heat exchangers in a transport refrigeration system.
As a natural and environmentally benign refrigerant, CO2 (R-744) is attracting significant attention as a refrigerant. Potential applications include transport refrigeration units (e.g., truck boxes, trailers, cargo containers, and the like) which require broad capabilities. A given unit configuration may be made manufactured for multiple operators with different needs. Many operators will have the need to, at different times, use a given unit for transport of frozen goods and non-frozen perishables. An exemplary frozen goods temperature is about −10° F. or less and an exemplary non-frozen perishable temperature is 34-38° F. The operator will predetermine appropriate temperature for each of the two modes. Prior to a trip or series, the technician or driver will enter the appropriate one of the two temperatures. Other operators may have broader requirements (e.g., an exemplary overall range of −40-57° F.).
In the HVAC art, use of economizer heat exchangers (economizers) is well known.